Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge.
In various locations in the ocean valuable seafloor materials, such as sulphide precipitates or polymetallic nodules, exist in a surface layer on the seafloor at water depths of between around 300 to 6,000 meters, often around 4,000 to 5,000 meters.
There have been various attempts to develop commercially viable mining systems that collect and then convey the nodules from the seafloor. Typically such systems are complex as several different actions need to be accounted for. For example, there can be seafloor mining machines which mine the seafloor, seafloor reclaimer machines which gather the seafloor material, and seafloor haulage systems, such as a riser, which hauls the gathered seafloor material to the surface. If these machines are integrated into a single mining system these all must operate simultaneously and co-operatively to obtain maximum output efficiency of the system.
However, as soon as one machine encounters a problem the entire production system halts or, at least, has reduced throughput. Furthermore, the large amount of infrastructure on or near the seafloor can create traffic problems with different machines or equipment getting in the way of other machines or equipment. Not only can this result in reduced productivity, but there can be collisions or entanglement of lines (e.g. umbilical lines) which can damage or reduce productivity of the machines or equipment.
A particularly costly part of the process relates to the surface vessel and associated haulage system. The surface vessel needs to be large enough to have a riser system extending towards the seafloor of a length sufficient to deliver the ore to the surface vessel. The weight associated with a riser system of this scope is significant and thus the surface vessel needs to be of a size to be able to carry that weight. Additionally, a significant amount of energy is expended in hauling the nodules to the surface. This leads to very high operating costs in reclaiming gathered seafloor materials, particularly when relatively small amount of nodules may be gathered in any given time period, or where water depths are great and the hauling vertical distance is large.